WO2021035617A1 - Système de détection capacitif, et circuit de détection et procédé de détection pour écran tactile capacitif - Google Patents

Système de détection capacitif, et circuit de détection et procédé de détection pour écran tactile capacitif Download PDF

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Publication number
WO2021035617A1
WO2021035617A1 PCT/CN2019/103312 CN2019103312W WO2021035617A1 WO 2021035617 A1 WO2021035617 A1 WO 2021035617A1 CN 2019103312 W CN2019103312 W CN 2019103312W WO 2021035617 A1 WO2021035617 A1 WO 2021035617A1
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current
voltage
sensing
circuit
input
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PCT/CN2019/103312
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English (en)
Chinese (zh)
Inventor
林永福
庄朝贵
徐嘉骏
徐建昌
徐荣贵
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深圳市汇顶科技股份有限公司
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Priority to CN201980001700.3A priority Critical patent/CN112805665A/zh
Priority to PCT/CN2019/103312 priority patent/WO2021035617A1/fr
Publication of WO2021035617A1 publication Critical patent/WO2021035617A1/fr

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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means

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  • the present disclosure relates to capacitive sensing technology, and in particular to a sensing circuit and sensing method of a capacitive touch screen, and a related capacitive sensing system.
  • the sensing circuit of the capacitive touch screen can detect the change in the capacitance value of the capacitive node caused by the touch object, and generate an output voltage accordingly as a detection result.
  • the variation range of the output voltage of the sensing circuit is usually increased as much as possible to increase the amount of signal generated due to the variation of the capacitance value.
  • a large part of the output voltage of the sensing circuit is the contribution from the input voltage, and the contribution from the change of the capacitance value only accounts for a small part of the output voltage.
  • One of the objectives of the present disclosure is to provide a sensing circuit and a sensing method of a capacitive touch screen, and a related capacitive sensing system to solve the above-mentioned problems.
  • An embodiment of the present disclosure provides a sensing circuit of a capacitive touch screen.
  • the sensing circuit includes a first conversion circuit, a first current mirror circuit, and a second conversion circuit.
  • the first conversion circuit is coupled to the sensing node of the capacitive touch screen, and is used for converting the charge accumulated by the sensing node into a first current according to a first input voltage.
  • the first current mirror circuit is coupled to the first conversion circuit for generating a second current according to the first current, wherein the second current is a copy or a multiple of the first current.
  • the second conversion circuit is coupled to the current mirror circuit for generating an output voltage in response to at least the second current.
  • the capacitive sensing system includes a capacitive touch screen and a sensing circuit.
  • the capacitive touch screen has a sensing node, and the sensing node generates a capacitance value change in response to a touch event on the capacitive touch screen.
  • the sensing circuit is used for sensing the change of the capacitance value.
  • the sensing circuit includes a first conversion circuit, a first current mirror circuit, and a second conversion circuit.
  • the first conversion circuit is coupled to the sensing node, and is configured to convert the charge accumulated in the sensing node into a first current according to a first input voltage.
  • the first current mirror circuit is coupled to the first conversion circuit for generating a second current according to the first current, wherein the second current is a copy or a multiple of the first current.
  • the second conversion circuit is coupled to the current mirror circuit for generating an output voltage in response to at least the second current.
  • An embodiment of the present disclosure provides a sensing method for a capacitive touch screen.
  • the sensing method includes: converting the charge accumulated in the sensing node of the capacitive touch screen into a first current according to a first input voltage; receiving the first current by a first current mirror circuit to generate a second current, wherein The second current is a copy or multiplication of the first current; and at least an output voltage is generated in response to the second current.
  • Fig. 1 is a functional block diagram of an embodiment of the capacitive sensing system of the present disclosure.
  • Fig. 2 is a schematic diagram of an embodiment of the sensing circuit shown in Fig. 1.
  • FIG. 3 is a schematic diagram of an embodiment of a sensing circuit of a sensing capacitive touch screen.
  • Fig. 4 is a schematic diagram of another embodiment of the sensing circuit shown in Fig. 1.
  • FIG. 5 is a flowchart of an embodiment of the sensing method of the capacitive touch screen of the present disclosure.
  • Fig. 1 is a functional block diagram of an embodiment of the capacitive sensing system of the present disclosure.
  • the capacitive sensing system 100 can be installed in an electronic device.
  • the electronic device may be implemented as a portable electronic device, such as a mobile phone, a tablet computer, a laptop computer, or other types of portable electronic devices.
  • the capacitive sensing system 100 may include (but is not limited to) a capacitive touch screen 110, a sensing circuit 120, and a processing circuit 130.
  • the capacitive touch screen 110 can use self-capacitance or mutual-capacitance sensing technology to detect a touch event TE on the capacitive touch screen 110.
  • the capacitive touch screen 110 may have multiple sensing nodes (or may be referred to as capacitive nodes; not shown in FIG. 1).
  • the capacitive touch screen 110 may have a plurality of driving electrodes arranged along a first direction and a plurality of sensing electrodes arranged along a second direction (not shown in FIG. 1), wherein the A plurality of driving electrodes are arranged on one electrode layer (not shown in FIG. 1), and the plurality of sensing electrodes are arranged on another electrode layer (not shown in FIG. 1).
  • Each sensing node may be located at (but not limited to) the intersection of a driving electrode and a sensing electrode in the capacitive touch screen 110.
  • a touch event TE occurs (such as a touch object touching or approaching the capacitive touch screen 110)
  • one or more sensor nodes of the capacitive touch screen 110 can respond to the touch event TE to generate capacitance changes to reflect the operation of the touch object behavior.
  • the sensing circuit 120 is coupled to a plurality of sensing nodes of the capacitive touch screen 110, and is used to sense the change of the capacitance value of each sensing node according to a first input voltage Vin (such as an analog voltage signal or an AC voltage).
  • An output voltage Vout (such as an analog voltage signal or AC voltage) is generated.
  • the sensing circuit 120 may include (but is not limited to) a first conversion circuit 122, a first current mirror circuit 125, and a second conversion circuit 126.
  • the first conversion circuit 122 is used for converting the charge accumulated in each sensing node into a first current Iout according to the first input voltage Vin.
  • the first conversion circuit 122 can perform a charge-to-current conversion operation on the charges accumulated by each sensor node.
  • the first current mirror circuit 125 is coupled to the first conversion circuit 122 for generating a second current Ix according to the first current Iout.
  • the second current Ix can be regarded as a copy or multiplication of the first current Iout, wherein the ratio between the second current Ix and the first current Iout is adjustable.
  • the first current mirror circuit 125 may have a programmable gain.
  • the second conversion circuit 126 is coupled to the first current mirror circuit 125 for generating an output voltage Vout in response to at least the second current Ix.
  • the sensing circuit 120 can first convert the charges accumulated by each sensing node in response to the first input voltage Vin into the first current Iout, Thus, the output voltage Vout is generated according to the copy (or multiplication) of the first current Iout.
  • the sensing circuit 120 can perform the charge amplification operation according to the current conversion result of the first input voltage Vin (the first current Iout or the second current Ix), instead of directly using the first input voltage Vin to perform the charge amplification operation, the transmission The sensing circuit 120 can reduce the contribution from the voltage variation range (such as the peak-to-peak value) of the first input voltage Vin in the voltage variation range (such as the peak-to-peak value) of the output voltage Vout. Further explanation will be given later.
  • the processing circuit 130 is coupled to the sensing circuit 120 to perform signal processing on the output voltage Vout to detect the touch event TE.
  • the processing circuit 130 may include a filter circuit 132, an analog-to-digital conversion circuit 134, and a signal processor 136.
  • the filter circuit 132 can filter the output voltage Vout to generate the filtered voltage Vf.
  • the filter circuit 132 may be implemented by a low-pass filter, such as an anti-alias filter, to reduce the noise component in the output voltage Vout.
  • the analog-to-digital conversion circuit 134 can convert the filtered voltage Vf into a digital signal Vd for the signal processor 136 to perform signal processing.
  • FIG. 2 is a schematic diagram of an embodiment of the sensing circuit 120 shown in FIG. 1.
  • the sensing circuit 220 may include (but is not limited to) a first conversion circuit 222, a first current mirror circuit 225, and a second conversion circuit 226.
  • the first conversion circuit 222, the first current mirror circuit 225, and the second conversion circuit 226 can be used to implement the first conversion circuit 122, the first current mirror circuit 125, and the second conversion circuit 126 shown in FIG. 1, respectively.
  • the first conversion circuit 222 is coupled to a sensing node NS of the capacitive touch screen 110, and is used for converting the charge accumulated in the sensing node NS into a first current Iout according to the first input voltage Vin.
  • the sensing node NS is coupled to a sensing capacitor CL , which can represent the equivalent capacitance formed between the driving electrode and the sensing electrode corresponding to the sensing node NS.
  • the first input voltage Vin may be implemented by an AC voltage, such as a sine wave voltage.
  • an AC voltage with a peak-to-peak value of 2 volts can be used to implement the first input voltage Vin.
  • the first conversion circuit 222 may include (but is not limited to) a voltage buffer 223.
  • the input terminal BFI of the voltage buffer 223 is used to receive the first input voltage Vin. Since the output terminal BFO of the voltage buffer 223 is coupled to the sensing node NS, the voltage buffer 223 can convert the charge accumulated in the sensing node NS into the first input voltage Vin according to the buffered version of the first input voltage Vin (that is, the buffer voltage Vbf). A current Iout.
  • the voltage buffer 223 can be implemented by a voltage follower, so that the buffer voltage Vbf can be a copy of the first input voltage Vin.
  • the voltage follower can be implemented by an amplifier 224, which has a first input terminal TI11, a second input terminal TI12, and an output terminal TO1.
  • the first input terminal TI11 is used to receive the first input voltage Vin.
  • the second input terminal TI12 and the output terminal TO1 are connected to each other and coupled to the sensor node NS.
  • the signal path between the sensor node and the second input terminal TI12 NS (such as a signal line or wire) of the equivalent resistance R L is represented by a resistor.
  • the output terminal TO1 is coupled to the first current mirror circuit 224 for outputting the first current Iout.
  • the first current mirror circuit 225 is used to generate a second current Ix according to the first current Iout, which can be a copy or a multiple of the first current Iout. It is worth noting that the first current Iout (which carries the charge accumulation information of the sensing node NS) may flow into the amplifier 224 through the output terminal TO1, instead of flowing outside the amplifier 224 (such as flowing from the output terminal BFO to the first current mirror). Circuit 225). In order to enable the circuit at the back end of the first conversion circuit 222 to receive the information carried by the first current Iout, the sensing circuit 220 can use the first current mirror circuit 225 to generate the second current Ix that flows to the circuit at the back end of the first conversion circuit 222. The charge accumulation information of the sensing node NS carried by the first current Iout can be transmitted later for processing by the back-end circuit (such as the second conversion circuit 226).
  • the back-end circuit such as the second conversion circuit 226).
  • the second conversion circuit 226 includes (but is not limited to) an amplifier 228 and a resistor-capacitor network 229.
  • the amplifier 228 has a first input terminal TI21, a second input terminal TI22 and an output terminal TO2.
  • the first input terminal TI21 is coupled to a reference voltage Vref, such as a common mode voltage or a ground voltage.
  • the second input terminal TI22 is coupled to the first current mirror circuit 225 for receiving a copy or multiplication of the first current Iout, that is, the second current Ix.
  • the output terminal TO2 is used to output the output voltage Vout for use by the next stage circuit (such as the processing circuit 130 shown in FIG. 1).
  • the resistor-capacitor network 229 is coupled between the second input terminal TI22 and the output terminal TO2 of the amplifier 228.
  • the resistor-capacitor network 229 may include (but is not limited to) a resistor R F and a capacitor C F.
  • the second conversion circuit 226 can amplify the charge information accumulated in the sensing node NS carried in the second current Ix, and According to this, the output voltage Vout is generated.
  • the first conversion circuit 222 may convert the charge accumulated in the sensing node NS into the first current Iout according to the first input voltage Vin.
  • the first current Iout (a function with real variables (time)) can be transformed into a function with complex variables.
  • the Laplace transform IOUT(s) of the first current Iout is equal to the product of the Laplace transform VIN(s) of the first input voltage Vin and the transfer function H1(s), And can be expressed by the following formula (1):
  • CL represents the capacitance value of the sensing node NS
  • RL represents a resistance value of the resistance L R.
  • the second conversion circuit 226 can generate the output voltage Vout in response to the second current Ix (a copy or multiplication of the first current Iout).
  • the Laplace transform VOUT(s) of the output voltage Vout can be derived from the product of the Laplace transform IOUT(s) and the transfer function H2(s) Means:
  • CF represents the capacitance value of the capacitor C F
  • RF represents the resistance value of the resistor R F.
  • the sensing circuit 220 can perform charge amplification according to the current conversion result of the first input voltage Vin (such as a copy (or multiplication) of the first current Iout). Operation, thereby greatly reducing the ratio of the voltage variation range (such as the peak-to-peak value) of the first input voltage Vin to the voltage variation range (such as the peak-to-peak value) of the output voltage Vout.
  • FIG. 3 shows an embodiment in which the current signal generated by applying the first input voltage Vin to the sensing node NS is directly used to perform the charge amplification operation.
  • the Laplace transform VOUT(s) of the output voltage Vout can be represented by the product of Vin's Laplace transform VIN(s) and the transfer function H4(s).
  • the charge accumulated on the sensing node NS will change with the change of the voltage level of the first input voltage Vin, resulting in a change in the capacitance value of the sensing node NS and a change in the current level of the first current Iout.
  • the voltage level of the output voltage Vout is changed. Therefore, the product of the Laplace transform VIN(s) and the transfer function H3(s) can correspond to the voltage variation range generated by the capacitance change of the sensing node NS in response to the first input voltage Vin, and the Laplace transform Converting VIN(s) corresponds to the voltage variation range of the first input voltage Vin.
  • the voltage variation range (peak-to-peak value) of the power supply voltage of the sensing circuit 320 is (but not limited to) 2.6 volts, and the voltage variation range (peak-to-peak value) of the output voltage Vout is set at (but not limited to) 2 volts or less
  • the 2 volt voltage variation range of the output voltage Vout is mostly derived from the voltage variation range (peak-to-peak value of the first input voltage Vin; Corresponds to the contribution of the Laplace transform VIN(s)).
  • the voltage variation range corresponding to the change in the capacitance value of the sensing node NS accounts for a relatively small proportion of the 2 volt voltage variation range.
  • the voltage variation range of the first input voltage Vin accounts for 80% of the voltage variation range of the output voltage Vout
  • the corresponding voltage variation range of the capacitance value change of the sensing node NS only accounts for 20% of the voltage variation range of the output voltage Vout .
  • the voltage variation range (peak-to-peak value) of the power supply voltage of the sensing circuit 220 is (but not limited to) 2.6 volts
  • the voltage variation range of the output voltage Vout ( Peak-to-peak value) is set at (but not limited to) 2 volts to maintain the operation of the circuit, because the Laplace transform VOUT(s) is equal to the Laplace transform VIN(s) and the transfer function H3(s)
  • the product is not the product of the transfer function H4(s) (the result of the addition of 1 and the transfer function H3(s)). Therefore, the 2 volt voltage range of the output voltage Vout corresponds to the change in the capacitance of the sensing node NS The voltage change range.
  • the capacitive sensing solution of the present disclosure can greatly reduce the ratio of the voltage variation range of the first input voltage Vin to the voltage variation range of the output voltage Vout, so it can increase the voltage variation range of the output voltage Vout.
  • the contribution of the change in capacitance of the sensing node NS can be increased.
  • the resistance value of the resistor R F can be increased to further increase the voltage change range corresponding to the change in the capacitance value of the sensing node NS.
  • FIG. 4 is a schematic diagram of another embodiment of the sensing circuit 120 shown in FIG. 1.
  • the structure of the sensing circuit 420 shown in FIG. 4 is roughly the same as/similar to the sensing circuit 220 shown in FIG. 2.
  • the sensing circuit 420 also includes a compensation circuit structure to more accurately obtain the sensor node
  • the capacitance value of NS changes. For example, when a touch event occurs TE (such as a touch objects touch / proximity capacitive touch screen 110), the sensing node NS can respond to the touch event generated TE capacitance variation, which sense capacitance by the shunt capacitance C L is represented ⁇ C L .
  • Sensing circuit 420 may employ a circuit configuration of the compensation capacitor ⁇ C L to obtain related information more accurately.
  • the sensing circuit 420 also includes (but not limited to) a storage capacitor C A, a third switching circuit 442 and a second current mirror circuit 445, wherein the auxiliary capacitance C A, and a third switching circuit 442
  • the second current mirror circuit 445 can be used as at least a part of the compensation circuit structure of the sensing circuit 420.
  • the first conversion circuit 222, a first current mirror circuit 225, a second conversion circuit 226, the storage capacitor C A, the third switching circuit 442 and a second current mirror circuit 445 may be implemented on the same chip.
  • the capacitance value of the storage capacitor C A may be equal to the capacitance value of the sensing node NS had before the occurrence of a touch event TE, L, such as the capacitance value of the sensing capacitance C.
  • the third switching circuit 442 to a second input of the auxiliary voltage VA of the charge accumulation capacitor C A is converted to a third currents IA, wherein the second input voltage VA having a phase opposite to the phase of a first input voltage Vin.
  • the second input voltage VA may be a sine wave voltage that is 180 degrees out of phase with the first input voltage Vin, where the first input voltage Vin and
  • the second input voltage VA may have the same amplitude.
  • the circuit structure of the third conversion circuit 442 may be substantially the same as the circuit structure of the first conversion circuit 222 to simulate a situation in which the first conversion circuit 222 generates a current signal in response to the accumulated charges of the sensor node NS before the touch event TE occurs.
  • the third switching circuit 442 may comprise a resistor R A and a voltage buffer 443.
  • the resistance value of the resistor R A L may be equal to the resistance of the resistor R.
  • the voltage buffer 443 can be implemented by an amplifier 444, which has a first input terminal TI31, a second input terminal TI32 and an output terminal TO3.
  • the first input terminal TI31 is used to receive the second input voltage VA.
  • a second input terminal and the output terminal TI32 TO3 contact with each other, and to the auxiliary capacitance C A is coupled via a resistor R A.
  • the output terminal TO3 is used to output the third current IA.
  • the second current mirror circuit 445 is coupled to the third conversion circuit 442 for generating a fourth current Iy according to the third current IA, which is a copy or multiplication of the third current IA.
  • the current gain of the second current mirror circuit 445 may be the same/similar to the current gain of the first current mirror circuit 225.
  • the difference between the current gain of the second current mirror circuit 445 and the current gain of the first current mirror circuit 225 may be 10%, 5%, 1%, or 10% of the current gain of the first current mirror circuit 225. Within 0.5%.
  • the fourth current Iy carrying the capacitance value information before the occurrence of the touch event TE can also be transmitted to The second conversion circuit 226.
  • the second conversion circuit 226 can generate the output voltage Vout in response to the second current Ix and the fourth current Iy.
  • the second voltage VA input to the first input voltage Vin same amplitude but opposite phase to each other, and the auxiliary capacitor C A and the sensing capacitor C can have the same capacitance value L with each other, and a third current IA a first current Iout current component in response to a first sensing capacitor C L input voltage Vin generated by the same amplitude but opposite phases to each other. That is, the third current IA generated by the third conversion circuit 442 can be used to eliminate/reduce the current generated by the sensing capacitor CL in response to the first input voltage Vin before the touch event TE occurs.
  • the fourth current Iy generated by the second current mirror circuit 445 can be used to eliminate/reduce the current component generated by the sensing capacitor C L in response to the first input voltage Vin in the second current Ix, so that the second conversion circuit 226 generates the information carried by the output voltage Vout most of the capacitance value of the capacitance variation ⁇ C L can be derived from.
  • the first current mirror circuit 225 can adaptively adjust the ratio between the second current Ix and the first current Iout, thereby improving the sensing quality. For example, when the noise of the surrounding environment is large, the first current mirror circuit 225 can reduce the current gain according to a control signal CS, where the control signal CS can be made by a back-end circuit (such as the signal processor 136 shown in FIG. 1) Generated by noise detection. In some embodiments, in the case where the first current mirror circuit 225 can adjust the ratio between the second current Ix and the first current Iout according to the control signal CS, the second current mirror circuit 445 can also adjust according to the control signal CS. The ratio between the fourth current Iy and the third current IA.
  • the first conversion circuit 222 may be implemented by other charge-to-current converters. That is to say, as long as it is a conversion circuit that can convert the charge accumulated in the sensing node NS according to the first input voltage Vin to generate the first current Iout, the design related changes are within the scope of the present disclosure.
  • FIG. 5 is a flowchart of an embodiment of the sensing method of the capacitive touch screen of the present disclosure. If the results obtained are substantially the same, the steps do not have to be performed in the order shown in FIG. 5. For example, certain steps can be inserted in it.
  • the capacitive touch screen 110 and the sensing circuit 420 shown in FIG. 4 are used to describe the sensing method shown in FIG. 5 below. However, it is feasible to apply the sensing method shown in FIG. 5 to the sensing circuit 120 shown in FIG. 1 and/or the sensing circuit 220 shown in FIG. 2.
  • the sensing method shown in Figure 5 can be briefly summarized as follows.
  • Step 502 Convert the charge accumulated in a sensing node of the capacitive touch screen into a first current according to a first input voltage.
  • the first conversion circuit 222 converts the charge accumulated in the sensing node NS into the first current Iout.
  • Step 504 Utilize a first current mirror circuit to receive the first current to generate a second current, wherein the second current is a copy or a multiple of the first current.
  • the first current mirror circuit 225 is used to receive the first current Iout to generate the second current Ix.
  • Step 506 Generate an output voltage in response to at least the second current.
  • the second conversion circuit 226 responds to at least the second current Ix to generate the output voltage Vout.
  • the voltage variation range generated by the change of the capacitance value of the sensing node NS in response to the first input voltage Vin is equal to the voltage variation range of the output voltage Vout. That is to say, the change of the capacitance value of the sensing node NS will cause the change of the charge accumulated on the sensing node NS with the first input voltage Vin.
  • the first input voltage may be coupled to an input terminal of a voltage buffer, and the sensing node may be coupled to an output terminal of the voltage buffer, so as to transmit the The charge accumulated in the sensing node is converted into the first current.
  • the first input voltage Vin may be received from the input terminal BFI of the voltage buffer 223 in the first conversion circuit 222, and the sensing node NS may be coupled to the output terminal BFO of the voltage buffer 223 to connect the sensing node The charge accumulated by NS is converted into the first current Iout.
  • the capacitive sensing solution of the present disclosure can also use current compensation to more accurately obtain the change in capacitance value generated at the sensing node in response to a touch event.
  • the third switching circuit 442 may be a first phase of the input voltage Vin input voltage VA will be opposite to the second storage capacitor C A is charged into a third accumulating currents IA, wherein the second input voltage VA in accordance with phase, and the capacitance value of the storage capacitor C a is equal to the TE event occurs before a touch sensor having a capacitance value NS node (L, such as a capacitance value of the sensing capacitance C).
  • the second current mirror circuit 445 receives the third current IA to generate the fourth current Iy.
  • the second switching circuit 226 may respond to the second and fourth current Iy current Ix generates an output voltage Vout of, most of the information they carry can be from a capacitance of the capacitor ⁇ C of change L.
  • the capacitive sensing solution of the present disclosure can greatly reduce the ratio of the input voltage variation range to the output voltage variation range.
  • the capacitive sensing solution of the present disclosure can further improve the sensing quality.

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Abstract

L'invention concerne un circuit de détection pour un écran tactile capacitif, un système de détection capacitive et un procédé de détection pour l'écran tactile capacitif. Le circuit de détection comprend un premier circuit de conversion (222), un premier circuit miroir de courant (225) et un deuxième circuit de conversion (226). Le premier circuit de conversion (222) est connecté à un nœud de détection (110) de l'écran tactile capacitif et il est utilisé pour convertir une charge accumulée par le nœud de détection en un premier courant en fonction d'une première tension d'entrée. Le premier circuit miroir de courant (225) est connecté au premier circuit de conversion (222) et utilisé pour générer un deuxième courant en fonction du premier courant, le deuxième courant étant une copie ou un multiple du premier courant. Le deuxième circuit de conversion (226) est connecté au circuit miroir de courant (225) et il est utilisé pour générer une tension de sortie au moins en réponse au deuxième courant. Le circuit de détection peut considérablement augmenter la contribution de la variation de la valeur de capacité du nœud de détection dans une plage de variation de tension de la tension de sortie.
PCT/CN2019/103312 2019-08-29 2019-08-29 Système de détection capacitif, et circuit de détection et procédé de détection pour écran tactile capacitif WO2021035617A1 (fr)

Priority Applications (2)

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CN201980001700.3A CN112805665A (zh) 2019-08-29 2019-08-29 电容式传感系统以及电容式触摸屏的传感电路和传感方法
PCT/CN2019/103312 WO2021035617A1 (fr) 2019-08-29 2019-08-29 Système de détection capacitif, et circuit de détection et procédé de détection pour écran tactile capacitif

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PCT/CN2019/103312 WO2021035617A1 (fr) 2019-08-29 2019-08-29 Système de détection capacitif, et circuit de détection et procédé de détection pour écran tactile capacitif

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CN102023737A (zh) * 2009-09-21 2011-04-20 奇景光电股份有限公司 电流式触控面板的读取装置
WO2016130070A1 (fr) * 2015-02-11 2016-08-18 Fingerprint Cards Ab Dispositif de détection d'empreinte digitale capacitive comprenant un affichage de courant à partir d'éléments de détection
CN107544703A (zh) * 2016-06-28 2018-01-05 瑞萨电子株式会社 半导体装置、位置检测装置和半导体装置的控制方法
CN109214252A (zh) * 2017-07-06 2019-01-15 敦泰电子有限公司 一种指纹感测电路及指纹感测装置
CN109976565A (zh) * 2017-12-27 2019-07-05 联咏科技股份有限公司 用于处理来自触控面板的感测信号的信号处理电路

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